pelton



- 2 Sheets-Sheet 1. G. M. PELTON.

VALVE GEAR.

(No Model.)

No. 374,752. Patented 960.13, 1887.

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(No Model.)

G.-M. PELTON.

VALVE GEAR.

7 8 I 8 V g m m k V. T W 6 D d e t n e t a P .NITED STATES ATENT Fries.

GEORGE M. PELTON, OF BELMONT, NEW YORK, ASSIGNOR TO \VILLIAM P. CLARKAND CHARLES E. CLARK, OF SAME PLACE.

vALvE-eEA R.

SPECIFICATION forming part of Letters Patent No. 374,752 dated December13, 1887.

Application filed December 1, 1886. Serial No. 220,358. (No model.)

To all whom it may concern: v

Be it known that I, GEORGE M. PELTON, a

citizen of the United States, residing at Belmont, in the county ofAllegany and State of New York, have invented certain new and usefulImprovements in Valve Gear, of which the following is a specification,reference being had therein to the accompanying drawings, in which-Figure 1 represents a plan,-with parts in section; Fig. 2-, a verticallongitudinal section through the line X X. Fig. 3 is an elevation (on alarger scale) of the governor, showing its connection with theeccentric. Fig. 4shows a section of the eccentrics also on a largerscale. Fig. 5 is an elevation of a modification. Fig. 6 is asection ofthe modification shown in Fig. 5, but with the parts in a differentposition.

This improvement relates to that class of cut-offs in which two valvesare usedone to admit and exhaust steam to and from the engine and theother to cut off the steam from the main valve; and the inventionconsists in the peculiar construction and arrangement and combination ofparts, hereinafter more particularly described,and then definitelypointed out in the claims.

Referring now to the details of the draw- 0 iugs, A represents the frameof the engine; B,

the cylinder; C, the piston-rod; D, the pitman, connected by thewrist-pin E with-the crank-disk F and shaft G, to give the latter motionin the usual manner. As nothing is 5 claimed on these parts, a fuller orfurther description is unnecessary.

Mounted fast on the shaft G is an eccentric, H, which, to distinguishfrom another one, I call the fixed eccentric, and which drives 0 themain valve I by means of the link J, which is pivoted to the valve-rodK. On the main eccentric is journaled a cut-off eccentric, L, connectedwith the cut-off valve M, that slides on the main valve, by the link Nand valve- 5 rod 0. This cut-off eccentric I intend to adjust on themain eccentric by any suitable connection with a governor, and asaspecimen of the style of governor I prefer to use I show one in whichweighted levers and springs are used, as indicated more particularly inFig. 3, in which 1? is a wheel or casecarrying .the eccentric, and itmay be placed on the pivoted weighted levers Q Q, which are connected bythe links R R with the cut-off eccentric L, and are provided withspringsS S, the ends ofwhich are connected to the levers and to thewheel or case in any convenient manner.

The weights T on the levers are provided with setscrews, by which theycan be set at the desired place on the levers. The valve I hasinlet-ports it and an exhaust-portJ; but the cutoff valve is withoutports, as it eonsists simply of two metal blocks, m m, connected by abar, at.

In the operation of this cut-off steam is admitted to the cylinder-portsb 5 through the ports 2' 'i in the valve I, and is exhausted through theport z". The closing of the" ports I) b and the opening of the exhaustalways occurs at fixed points in each stroke, being governed by the mainor fixed eccentric; but the closure of the inlet-ports t i in the valveI is varied by the cut-off eccentric L, the position of which iscontrolled by the governor-weights T T. In maintaining the equilibriumbetween the flying weights T and the springsSSasthe engine varies inspeed, the weights will move out and in, thus varying the position, ofthe eccentric, and consequently the cut-off valve, accordingly, andclosing the ports i i at an earlier or later period in the stroke,giving a greater or less amount'of steam, according to the variation ofthe load on the engine.

Although the time of cutoff of the cut-off valve'varies, as shown, thetravel of the cut off valve on its seat on the back of the main valve isalways the same, owing to the fact that the centers of the cut-offandmain eccentries are fixed relatively to each other. This is veryimportant, for if the travel of one valve on the other varied, as itwould if the two eccentrics were not concentric with each other, itwould Wear the surface of the lower valve unevenly, causing leakage. Byjournaling the cut-off eccentric on the main eccentric it enables meto'connect the cut-off 5 eccentric directly to its valve withoutintervening mechanism. v

Figs. 5 and 6 show a modified form of my invention that accomplishes thesame effect as outer end of the main shaft B or on aseparate shaftdriven from the main shaft, if desired.

and is connected to the flying weight T by I means of the arm XV andconnecting-link It. It is evident that either of these devices-viz., theeccentrics or the cranks-may be used to give the motion to the main andcut-ofi'valves,

and I should consider the cranks as an equivalent for the eccentrics,and mean to be understood as claiming the eccentrics, the cranks shown,or any equivalent for them when using the word eccentrics in thefollowing claims.

It is evident that the cut-off eccentric might be mounted on aneccentric collar independent of the main eccentric, but having itssurface concentric with the acting-surface of the main eccentric, whicharrangement I should consider as the full equivalent of that heretoforedescribed and shown, as it is obvious that it makes no differencewhether the eccentric collar onwhich the cut-offeccentric is mounted isin one piece with the main eccentric or is separate therefrom.

I am aware that a movable eccentric controlled by a governor for workinga cutoff valve had been mounted on a fixed eccentriceccentricall y tothe acting-surface of said fixed eccentric, as shown in the EnglishPatent No.

2,213 of 1859, and make no claim to the same,

as I consider my invention essentially different from the arrangementshown in the patent referred to, for in that case, when the adjustableeccentric is changed, the cut-off valve travels over a place on the mainvalve different from that it did before the change of the eccentric wasmade. This is objectionable for the following reason: When the cutoffvalve has been traveling for some time over one part of the surface ofthe main valve, a certain amount of wear takes place, so that thesurface of the main valve traveled over by the cut-off valve is slightlylower than the other part of the valve. If the eccentric is now changed,the cutoff valve travels over a portion of the valve that has beenpreviously worn and over another portion of the valve which has not beenworn, and a leak is therefore caused by the difference between the wornand uuworn surfaces. This is avoided by my arrangement, for the cut-offvalve always travels over precisely the same surface on the.

main valve, no matter how much the eccentric is shifted- Consequentlythe wear is always even, and thus leakage is prevented.

Having thus described what I consider the preferable form of myimprovement, but without limiting myself to the construction shown, Iclaim as new- 1. The combination, in an engine, of main and cut-offvalves and an eccentric connected to a governor for controlling thecut-0E valve and journaled concentrically to the actingsurface of themain eccentric, whereby the rubbing-surfaces between the two valvesremain always the same, substantially as described.

2. The combination, with the shaft of an engine, of two eccentrics, oneof which operates the mainvalve and is fast on the shaft,

and the other is connected with the cut-off.

valve and journaled concentrically to the acting-surface of said fasteccentric and arranged to turn around the same, whereby the rubbingsurfaces between the two valves always remain the same, substantially asdescribed.

3. The combination, with the shaft of an engine, of two eccentrics foroperating the valves thereof, one of which is fast on said shaft and theother journaled concentrically to the acting-su rfaoe of said fasteccentric and constructed and arranged to turn around the same, wherebythe rubbing-surfaces between the two valves remain always the same,substantially as and for the purpose specified.

4. The combination, with the main shaft G of an engine, and as a meansof operating the valves thereof, of the eccentric H, fast on said shaft,and a loose eccentric, L, j ournaled on said fast eccentric and turningconcentric with its center, whereby the rubbing'surfaces between the twovalves remain always the same, substantially as described.

5. The combination, with the main shaft and valves of an engine, of theeccentrics H and L, the former fast on the shaft and the latterjournaled on the eccentric H, concentric with the acting-surfacethereof, the governor Q Q and S S, the links R, connecting the governorto the eccentric L, and the link J N,

ICC

connecting the eccentrics to the valves, substa'nt-ially as and forthepurpose specified.

In testimony whereof I afiix my signatnre,in presence of two witnesses,this 29th day of November, 1886.

GEORGE M. PELTON.

VVit-nesses:

CHARLES E. CLARK, J. N. HYDE.

